Development of analytic system of brushing strokes and computer assisted instruction system

对刷牙运动进行三维运动捕捉和运动分析。志愿者的牙刷、脸、右手、手臂、肩膀和胸部都贴着37个球形标记。使用5台摄像机进行视频图像采集，使用Ishikawa等人开发的无需摄像机校准的算法对视频图像进行运动恢复处理。用三种不同的技术记录30秒的刷牙动作，间隔为每秒10帧。静止帧被编辑以生成标记位置的三维图。总共有322个火焰和11714个标记物被纳入运动分析。生成了“刷线”模型的三维重构运动图像。这样就可以从各个方向观察到刷牙的运动。此外，提取特定标记的连续运动，以评估它们对笔触的贡献。利用三维图计算各标记物的振幅、速度和加速度以及标记物的能量消耗。动作捕捉技术使表征刷牙过程中的关节和特定标记物动力学成为可能。突出特定关节的运动将帮助患者意识到他们刷牙运动的任何特点。分析与笔触相关的特定标记的特征，有助于对刷牙技能水平的批判性评价和有效的刷牙指导。

Three-dimensional motion capture and movement analysis was performed on tooth brushing motion. There were 37 ball-shaped markers attached to the toothbrush, face, right hand, arms, shoulders and the chest of the volunteer. Video image capture was performed with 5 video cameras and the video images were processed for the motion recovery using camera calibration free algorithm developed by Ishikawa et al. Thirty seconds of brushing motion with three different techniques were recorded at intervals of 10 frames per second. Still frames were edited to generate three-dimensional plots of the marker positions. In total, 322 flames and 11714 markers were included for the motion analysis. Three-dimensionally reconstructed motion pictures of "brushing" wire-fame model was generated. That allowed observation of the brushing motion from all directions. Further more, extraction of the sequential movement of specific markers was achieved to evaluate their contributions to the brushing strokes. The amplitude, velocity and acceleration of each marker could be calculated using the three-dimensional plots together with energy expenditure of markers. Motion capture technique made it possible to characterize joint and specific marker kinetics during tooth brushing. Highlighted movement of specific joints will help patients realize any peculiarities of their brushing motion. Analysis of characteristics of specific markers related to brushing strokes will help with critical evaluation of the skill levels of the brushing and the effective brushing instruction.